The present invention relates generally to automotive lighting assemblies and methods of assembling automotive lighting assemblies. In particular, the present invention relates to a means for attaching a lens to a housing of an automotive lighting assembly while a structural adhesive cures.
Automotive lighting systems generally include a housing, a light source such a light fixture and bulb, a reflector which can be part of the housing and an overlying lens. The housing and lens are typically separately formed by injection molding of plastic. The lens, which can be clear or have a transparent color such as red or amber, serves to cover and protect the light fixture and bulb and protect the interior of the assembly from the elements while a vehicle travels down the road. The complete assembly is mounted in a predesigned recess on the body of the automobile so that the assembly mounts aerodynamically flush with the body.
Lenses for automotive lighting assemblies must be fixedly attached to the housings of such assemblies and sealed to prevent ingress of moisture and debris. Generally, structural adhesives can be used to accomplish such attachment. Typical adhesives are curable adhesives that harden over time either though chemical reaction or drying and may include such curable adhesive as epoxy adhesives, acrylic adhesives, polyurethane adhesives, silicone adhesives, anaerobic adhesives, cyanoacrylate adhesives, phenolic adhesives, polymide adhesives, plastisol adhesives, and polyvinyl acetate adhesives.
Unfortunately, upon application, curable adhesives need time to cure before a lens will become fixedly attached to the housing. During this curing period, a lens has a tendency to move from its desired mating position with the housing thereby compromising the attachment and/or the seal unless the lens is held stationary with respect to the housing. Thus, lenses in automotive lighting systems utilizing structural curable adhesives for attachment to housings have required one of various prior art types of xe2x80x9ctemporaryxe2x80x9d attaching means while the adhesives cure. Such means currently known in the art include sonic tacking, lens clips, and snaps. These temporary attaching means, however, require special manufacturing tools or additional labor steps, and result in increased labor and tooling costs. For example, additional mechanical means, such as lens clips or snaps require additional parts, tooling or labor steps to attach. While sonic tacking does not require additional parts per se, it does require an extra assembly process and special equipment. These additional parts, equipment or assembly processes result in a more expensive, labor intensive assembly. Such a result is undesirable where it is a common goal to reduce the overall cost of the vehicle.
Therefore, it is desirable object of the present invention to provide a simple, economical means, other than those prior art methods briefly described above, for securing a lens to the housing of an automotive lighting assembly while a structural adhesive cures that does not involve additional labor steps, parts or special equipment.
The present invention comprises a means and method for attaching an automotive lighting lens to the housing of an automotive lighting assembly while a structural adhesive cures. An automotive lighting assembly in accordance with the present invention comprises a housing having a recessed hollow portion dimensioned to enclose one or more light fixtures and having an open end with a peripheral edge around said open end. Formed around the periphery of the housing is a sealing groove and a plurality of engaging openings formed adjacent said groove. The engaging openings have a plurality of protuberances projecting into the opening, the protuberances providing a reduced area of clearance within the engaging opening. A covering lens has an exterior edge and one or more transparent windows for passing light. The lens has a flange dimensioned to extend into and mate with the sealing groove formed around the edge of the lens. A plurality of projections are formed on the lens and positioned to coincide and mate with the engaging openings and dimensioned to have a cross section that causes the projections to engage the protuberances to produce frictional engagement and retention when the projections are inserted into the engaging openings. A curable adhesive positioned within the sealing groove so that when the lens is pressed onto said housing so that the flange mates with the groove, and the projections frictionally engage the openings, the lens is retained in position until the curable adhesive cures sealing said flange in said groove.
The projections are typically cylindrical in shape and the protuberances have a pointed apex. The pointed apexes may be the corners of squared shaped projections that extend into the openings. The curable adhesive can be any one of a number of well known industrial curable adhesives and typically may be selected from the group epoxy adhesives, polyurethane adhesives, silicone adhesives, anaerobic adhesives, cyanoacrylate adhesives, acrylic adhesives, phenolic adhesives, polymide adhesives, plastisol adhesives, and polyvinyl acetate adhesives.